Anatomy

The suprascapular nerve originates from the fifth and sixth anterior cervical roots, which are part of the upper trunk of the brachial plexus. The suprascapular nerve typically is a motor nerve with no cutaneous sensory capabilities. It travels laterally, across the posterior cervical triangle, deep to the posterior belly of the omohyoid muscle and the anterior border of the trapezius muscle, along the posterior border of the clavicle.

The nerve then reaches the upper border of the scapula, where it passes through the suprascapular notch, which can have various shapes (e.g., “U” or “V”) and can be either deep and narrow or shallow and wide. While the nerve travels under the transverse scapular ligament as it passes through the notch, the suprascapular artery and vein travel over the ligament.

Beyond the transverse scapular ligament, the suprascapular nerve sends off one or two motor branches to the supraspinatus muscle, and it receives several sensory fibers from the glenohumeral joint, the acromioclavicular (AC) joint, the coracohumeral ligament and in 15% of patients, cutaneous sensory fibers from the upper lateral arm (deltoid patch). The nerve continues obliquely under the supraspinatus muscle along the floor of supraspinous fossa toward the rim of the glenoid.

The nerve then enters the infraspinatus fossa via the spinoglenoid notch, which lies at the lateral margin of the base of the scapular spine. The spinoglenoid notch may be covered by the spinoglenoid ligament, also known as the inferior transverse scapular ligament. After the nerve passes around the spinoglenoid notch, the nerve divides into two or more branches to supply the infraspinatus muscle.